Wednesday, November 25, 1998

Meat equivalent for vegetarians
By Dr K. C. Kanwar
PULSES, also termed legumes or beans, are podded seeds of leguminous plants. Beans is a collective term applied to the tender edible pods as well as used for the seeds of various such plants.

Needle prick from the HBV-infected
By Dr Yogesh Chawla
An accidental prick to a person from an HBsAg positive individual may lead to the transmission of HBV infection depending on the viral and the host factors.

Focus on hepatic hydatid disease
Therapy
By Dr R. Kochhar

New vaccine to ‘cure’ AIDS
By Michel W. Potts
PLEASANTON (California), Nov 17 — An Indian American neurologist has filed an application at the International Patent Office in Geneva to register a recumbent virus vaccine he has designed which he believes will eradicate the HIV virus long before it becomes full-blown AIDS.

A way to prevent tooth decay
A weapon from plants
A novel vaccine made from plants could end unpleasant visits to the dentist, says a British scientist.

Meat equivalent for vegetarians

By Dr K. C. Kanwar

PULSES, also termed legumes or beans, are podded seeds of leguminous plants. Beans is a collective term applied to the tender edible pods as well as used for the seeds of various such plants. Many varieties of beans are grown exclusively for their tender pods to be used as green vegetable, e.g., the French beans, string beans and "lobia". These are profitably grown only in places where the growing season is long enough to permit repeated pickings. Otherwise, beans are cultivated for their fully grown seeds which are either used fresh (green peas) or dried (e.g. dried peas, Bengal grams, chickpeas, navy and lima beans, varied lentils and pulses).

There are approximately 2000 known legume plants that produce the edible seeds variedly known as beans, lentils, pulses, grams etc. Many a time these terms are used synonymously. Dried beans display a bewildering variety of colours — from uniformly dark-brown, green, creamy-white or inky-blacks to varyingly stippled and speckled with fast colours. Pulses (the Indian equivalent — dal) also known as grain legumes , belong to the genus Phaseolus and are grown as field crops. The major pulses grown the world over comprise the field peas, chickpeas, fabia beans, lentils, lupins and perhaps many more.

In India the most common pulses are moong, urad, masoor, rajmah, lobia and rongi, which are consumed either as whole, split, dehusked and in certain cases even in powdered form such as besan. Many pulses, when appropriately processed, make the choicest snacks. Pulses can be profitably fractionated into three components viz. fibre, starch, proteins and these can be added at will to fortify many of the processed food products. The use of pulses as snacks and high-protein food or in pasta has a lot of scope to flourish.

Pulses are grown in rotation with cereals and oilseeds to improve soil fertility. The suitability of land for the production of pulses varies with soil types and average annual rainfall. These grow well even in poor soils. They are better suited to alkaline soil except lupins which perform better in acidic one. Many a time, the beans are cultivated simply to enrich soil since these plants have the unique property of taking up nitrogen (the essential plant nutrient) from air with the help of nitrogen-fixing bacteria lodged in their root nodules, and add this to the soil where it serves as a fertiliser.

Pulses, earlier in the developed world, were mainly used in the stockfeed industry. But not any more. Of late, the use of these in the food industry is increasing rapidly owing to their unique nutritional attributes and increasing consumer awareness. The world demand for pulses is increasing every year because these constitute an affordable rich source of protein, especially in the underdeveloped and developing world. The adoption of low-fat diets and the ever-growing tilt towards vegetarianism in the West, it is felt, will further escalate the demand for pulses globally.

According to the current estimates dry beans or pulses are a healthier and less expensive source of proteins for over two billion people worldwide. Beans are nutritively crucial for those who are habitually or compulsively vegetarians. For them, these constitute the meat equivalent.

Pulses/beans have all the plus points of providing healthy and nutritious food. They are rich in the much-needed proteins, low in fat and high in complex carbohydrates. They constitute a good source of minerals.

These contain high levels of resistant starch and the much needed fibre which tend to suppress appetite and hence their relevance in weight control programme. A diet rich in pulses ensures the desired supply of the fibre which in turn, lowers blood cholesterol — the main-villain of cardiovascular diseases — and helps fight colon cancer. The soluble fibre in the beans also helps maintain constant blood sugar levels — a boon for the diabetics.

According to Patti Geil of Kentucky University, a cup of boiled beans a day actually lowers the blood cholesterol level by an average of 10 per cent. Also low-fibre pulses like dehusked moong are extremely useful in providing adequate nutrition during convalescence and after a bout of diarrhoea when patients need easily digestible yet nutritious food.

The bean proteins, though abundant, are rated somewhat inferior in quality; these are particularly low in sulphur-containing amino acid methionine. Fortunately, methionine is found in plenty in the cereals (wheat and rice) which lack lysine — the amino acid abundant in pulses. Pulses, when consumed along with cereals make good the deficiency of each other through mutual supplementation. Dal-roti — a basic dietary concept of the poor in India — is a healthful combination though bereft of vitamins.

The nutritive value of the pulses or beans can further be improved, if these are allowed to sprout before being used as salad; sprouted beans are less calorific and far more nutritious than before. Sprouting (germination) tends to improve immensely their digestibility. The sprouts almost instantaneously acquire a battery of enzymes capable of breaking down proteins into amino-acids, starch into simple sugars and fats into fatty acids rendering them more easily digestible and assimiable.

The sprouts are excellent to those trying to slim down and lose weight. For example in the sprouted moong, the overall energy decreases by 15% but the protein availability increases by a whopping 30%. The carbohydrate molecules during sprouting are broken down and these, when they react with nitrogen, go to form amino-acids which, in turn, give rise to easily digestible proteins.

During sprouting, the trypsin inhibitors, which are commonly present in the raw pulses and impair their digestibility, are also inactivated. Further vitamins (A, B-Complex, C) are also rapidly synthesised during germination and, therefore, increase. In moong sprouts the vitamin A content increases by 285%, thiamine by 208%, riboflavin by an astounding 515%, niacin by 256% and finally ascorbic acid by 600%. When the seeds sprout, shoots appear earlier than roots. The sprouts are maximally nutritious, if consumed before the roots start emerging.

Sprouts are considered an excellent and inexpensive substitute for expensive fruits since both are rich in fibre and vitamins. Sprouts are also a rich source of assimiable minerals such as calcium, magnesium, phosphorus, potassium and zink. In moong sprouts, the availability of calcium increases by 34%, potassium by 80%, iron by 40% and phosphorus by 56%. This is attributable to the release of minerals from protein complexes and decrease in the level of phytates during sprouting. Further, beans like fruits, are low in sodium and high in potassium which in particular render them health-friendly and ideal for the hypertensive.

All this establishes the usefulness of sprouted beans in the menus. Sprouts should preferably be eaten either raw or following brief steaming lest they lose much of the vitamins. The seeds, more suitable for sprouting comprise kala chana or moong and certain other lentils.

Nutritionally, beans bring with them as much, if not more, protein as meat for much fewer calories and no artery-blocking fat and cholesterol. On an average, 27% of the calories in beans come from proteins and only 6% from fat as against beaf steak in which 20% of the calories come from proteins and 72% from fat. Compared to cereals which contain 7-12% proteins, pulses contain about 20-30% proteins. In soyabean, the protein content is as high as 40%. Whole pulses are more nutritious than their corresponding split dehusked forms.

Cooking, especially of big beans, is very time-consuming, particularly if these are not soaked overnight. Pressure-cooking is unavoidable especially at higher altitudes. Hard water should be avoided for boiling beans since it delays their softening necessitating prolonged boiling. Keep off tomatoes or anything acidic like tamarind and raw mango powder (amchur) until the beans are fully boiled and tender. Acidic pH of the cooking medium toughens the cell walls which retards the softening of the beans. The cooking time of the hardly beans can be cut down considerably by adding a small dash of baking soda which renders the cooking water alkaline, which accelerates the softening of the beans. However, baking soda, if used in excess, destroys vitamins of the B-group, especially thiamine, and hence should be avoided.

Many people prefer to avoid beans. These are known to produce gas. Beans, after all, are seeds rich in indigestible sugars which serve as the reserve nourishment for the seed at the time of germination. These complex and indigestible sugars comprise alpha galactosidases which humans cannot digest. However, this component, when it passes through the lower intestine, is broken down with the help of bacteria residing in the colon and in the process gases (methane and carbon dioxide) are produced.

The dietetics have developed a technique to take away flatulence of the beans. Soak the beans overnight and boil the same for about five minutes, turn off the heat and let these be further soaked for a few more hours. Discard the water and with this are discarded the indigestible gas-producing sugars. Boiling softens the seed cell walls which allow the offending sugars to leach out.

A single round of boiling and soaking removes approximately 85% of the offending component thus spelling relief for the users. Boiling and then discarding the boiled water do result in leaching out of some nutrients, for example the skin pigments, and minerals. Allowing such a loss is perhaps the lesser of the two evils, the scientists feel. The loss of minerals get easily compensated from other dietary sources. Proteins and fibre for which the beans are primarily preferred are not destroyed by such a procedure.

Dr Kanwar is a former Professor and Chairman of the Biophysics Department of Panjab University.

Needle prick from the HBV-infected
By Dr Yogesh Chawla

An accidental prick to a person from an HBsAg positive individual may lead to the transmission of HBV infection depending on the viral and the host factors. If the needle prick is from an HBsAg and HBeAg positive individual (HBeAg indicates infectivity, replication and hepatocytic necrosis) the blood in the needle is likely to carry many more HBV virus particles (106 virions/ml) than an HBeAg negative individual. This explains the higher incidence of transmission from HBeAg positive than anti-HBe positive carriers. Blood in the needle stick of the HBeAg positive patient may have >103 virions/ml. With an HBeAg positive needle prick, transmission of the HBV infection is likely to be 19-27 per cent as compared to a 3-5 per cent chance with an HBeAg negative source.

Needle prick to an immunosuppressed individual is more likely to develop chronic liver disease following the needle prick.

What to do following the prick?

The site of the prick needs to be immediately washed. If the victim has recently been immunised anti HBs titre > 100 IU/L or gives the past history of acute hepatitis B, he does not need immunisation. It is best to determine the anti HBs titres in this vaccinated individual. If his anti-HBs is positive in low titres (i.e. <10 IU/L) one booster dose of the hepatitis B vaccine is sufficient. If he has not been vaccinated, passive immunoprophylaxis should be imparted by administration of Hepatitis B immune globulin (HBIG) which is prepared from pooled plasma that contains a high titre of anti-HBs. The recommended dose of HBIG (200 iu/ml) of anti HBs) for adults is 0.05-0.07 ml\ kg body weight given as early as possible post-exposure. It should be given within 48 hours but not later than seven days post-exposure. In immunosuppressed individuals a second dose is recommended after 30 days.

The mode of action of HBIG in preventing HBV transmission is uncertain. The titre of anti-HBs is serum after HBIG administration attenuates and delays rather than preventing HBV transmission. Co-administration of HBIG does not interfere with subsequent response to active vaccination, provided they are injected at different sites.

Following the needle prick, the individuals should also have active immunisation with either a plasma derived or recombinant HBV vaccine as soon as possible (20 ug/ml). The HBsAg in the vaccine induces development of anti-HBs, which is protective, and also induces T-cell dependent immunity. The vaccine should be given intramuscularly in the deltoid muscle as gluteal injection leads to an inadequate response. A rapid vaccination schedule of 0, 1 and 2 months should be given in such an individual to achieve a higher and greater anti HBs response. As many as 85-95 per cent individuals after vaccination develop detectable anti HBs. The duration of anti HBs is related to the peak titre.

A small proportion, that is, immunosuppressed obese, old age individuals may not respond adequately to the vaccine. These individuals may need a fourth dose.

Subjects having renal failure should be given double dose of vaccine, i.e. 40 ug at 0, 1, 2, and 6 months.

In conclusion both passive and active immunisation should be practised for an individual exposed to an HBsAg positive infected needle prick. (Courtesy: Prof V. K. Kak)

Dr Chawla is Additional Professor in the Department of Hepatology, PGI, Chandigarh.

Focus on hepatic hydatid disease
Therapy
By Dr R. Kochhar

The non-surgical treatment of this disease can be summed up thus:

1. Chemotherapy

Mebendazole inhibits glucose uptake in susceptible parasites but it is poorly absorbed from the gut. Dosage ranging from 40-130 mg/kg/day for months have been tried without satisfactory results.

Albendazole is an effective scolicidal agent with a dose of 10 mg/kg/day achieving a cyst concentration of over 100 ng/ml. Treatment is given in cycles of 28 days with 2 weeks treatment-free period for (a) inoperable cases — as primary treatment — 3 cycles, (b) pre-operatively — to reduce the risk of recurrence — 6 weeks continuous treatment and (c) post-operatively to prevent recurrence in intra-operative cyst spillage-3 cycles. Cure rate (disappearance) is about 30% and improve ( >25% reduction in cyst size) is seen in 40%. Side-effects occur in 10% patients.

Praziquantel is an even more effective scolicidal agent than albendazole in a dose of 50 mg/kg/day, but albendazole is more effective on the germinal membrane of cysts. Praziquantel is recommended for pre-operative sterilisation and post-operative spillage. A combination of these two agents has proved better.

II. Percutaneous drainage (PD)

It has been shown that the risk of anaphylactic shock following PDis negligible. The cysts are first aspirated under ultrasound guidance followed by injection of a sclerosing agent (10% hydrogen peroxide, 20% saline, 0.5% cetrimide and 95% ethanol) which is aspirated out after 20 minutes. Results of this technique combined with oral albendazole are comparable to those of surgery.

III. Endoscopic management

Sphincterotomy with or without nasobiliary catheter/biliary stent is indicated for (a) acute cholangitis due to ruptured hydatid cysts(b) choledochal clearance of hydatid debris in CBD, avoiding CBD exploration and (c) post-operative biliary fistula.

(Courtesy: Prof V.K. Kak and GMC, Chandigarh.)

Dr Kochhar is Associate Professor in the Department of Gastroenterology, PGI, Chandigarh.

New vaccine to ‘cure’ AIDS
By Michel W. Potts

PLEASANTON (California), Nov 17 — An Indian American neurologist has filed an application at the International Patent Office in Geneva to register a recumbent virus vaccine he has designed which he believes will eradicate the HIV virus long before it becomes full-blown AIDS.

Known as Contre-Vir and developed by Sateesh Apte, who heads his own ImmunoScience Company here, the vaccine is being touted as a "definitive, immune mediated "cure" that requires only two injections.

"I’ve studied how the HIV affects the immune system, how it forms antibodies, and in that I discovered that removing the NEF (negative factor) gene from the virus renders it non-pathogenic," Apte told the California newspaper India-West. "Thus, we have an organism, like the cow pox virus that prevents small pox, that infects humans but doesn’t kill them, and that it what we wanted."

With a humanitarian wavier from the Indian Health Minister, Apte claimed that in 1994 he injected his vaccine into two Indians suffering from AIDS whose immune systems were on the verge of collapse. Their T-cell count soon rose to normal levels and, four years after the injections, they were healthy and virus free, he claimed.

While a normal T-cell count is between 800 and 1,000, the T-cell count in both patients 30 months after the tests climbed to well over 1,000, "and that is something that needs further study," Apte admitted.

Apte is in the process of raising $ 5 million to conduct double-blind clinical trials on 20 patients in South Africa and Russia "where we have approval to do it on a fast-track," he stated, since testing under the U.S. Federal Drug Administration (FDA) could take years. "We should have a definitive result within one year of the study of this process," he declared.

Though he has not published any papers as yet for peer review, "I have spoken to two scientists at L’Institut Pasteur in Paris who are working on a similar theory using a more cumbersome approach, but only as a preventive vaccine, not as a cure," Apte said.

A graduate of B.G. Medical College in his home town of Pune, Apte did collaborative research in 1976 at the Pasteur Institute which a little more than a decade later discovered the HIV virus. Following a stint as a Fellow at the Stanford Medical Centre, Apte went into private practice and formed ImmunoScience in 1995 largely to handle the manufacture of his Salivax Diagnostic Test kit.

Salivax, used by doctors for dignosing the HIV virus, Hepatitis B and C, syphilis and tuberculosis, was developed by Apte who, in his travels around the world, saw the need for such a product in developing countries where there are no diagnostic facilities in the rural areas.

"Since drawing blood is very dangerous (Salivax) is a non-invasive way of diagnosing (these diseases) that would be room-temperature stable and can be done by people with minimal training," Apte pointed out.

The FDA has approved Salivax for export but it is not available for distribution in the USA because registering the product "will cost an inordinate amount of money and jack up the price of our test kits abroad," Apte explained. "So we are perfectly satisfied with having an export licence."

— India Abroad News Service

A way to prevent tooth decay
A weapon from plants

A novel vaccine made from plants could end unpleasant visits to the dentist, says a British scientist.

Application of this new oral vaccine directly on teeth for over three weeks could free mouth from decay-causing bacteria for about six months, reports Discover.

Tooth decay is caused by the action of the bacterium streptococcus mutans, which develops on sugars sticking to teeth. The bacterium secretes acids as waste, which erode tooth enamel — the protective convering on it.

Julian Ma, an immunologist from the Guy’s Hospital in London, succeeded in creating antibodies to S mutans in laboratory, but the process was very expensive.

A more viable alternative, Ma found, was to use plant’s machinery to churn out antibodies by transferring the antibody genes into the genetic material of tobacco plants.

Not only could it prune costs, but plants were found to be extremely good at putting antibodies together.

The antibodies come in two different forms one that circulates in the bloodstream, and a more complex version, found in secretions like saliva.

The latter has a special protein chain that wraps around the rest of the antibody, protecting it from protein-munching enzymes in saliva.

Though the system is yet to be perfected, Ma says the same model can also be applied to treat various infectious diseases like common cold, sore throat, urinary tract infection and chest infection.