COMBATING CANCER OF BROCCOLI FIGHTS CANCER
COMBATING CANCER OF BROCCOLI FIGHTS CANCER
The word ‘cancer’ brings many dreadful thoughts, raises anxiety and fills the victims with feelings of utter helpnessness, for invasive cancers are invariably fatal despite several conventional treatments. The trauma of being diagnosed with cancer is indescribable, as one may experience a sudden jolt with a seemingly abrupt end to one’s life in sight. Perhaps, it is only true in cases of invasive cancer where cancer cells have begun to move to other body parts. For most cancers, if detected in the early stages, there are fairly good chances that the person might recover with a combination of different treatments.
Normally, there are three treatment choices. The first is conventional treatment, which includes chemotherapy, surgery and radiation therapy. The second option includes a wide range of alternative therapies, and the third is an ‘integrative’ approach which is a combination of these two therapies. Success rate of the efficacy of these treatments, however, declines as cancer progresses.
Some patients and physicians choose to use an integrative approach using a combination of conventional and alternative therapies. The primary concern of the cancer specialist (oncologist) is that some alternative therapies may interfere with the effectiveness of conventional treatment, like chemotherapy. Therefore, an alternative therapy can be tried if serious side effects are not anticipated and interference with conventional therapy is minimum.
The primary carcinogens stem from a variety of agricultural, industrial, and dietary factors. There are many natural products that have shown promise in cancer prevention and that promote human health without recognizable side effects. These molecules originate from vegetables, fruits, plant extracts, and herbs.
Therefore, one of the alternative approaches is through the use of herbal medicines that can reduce tumor growth and perhaps limit metastasis. These medicines can be taken internally or applied over the tumor as a paste. In the classical Ayurvedic literature, there are many complex formulations mentioned for the treatment of various types of cancers/tumors. Below are a few examples of anti-cancer herbs:
Manjishta (Rubia cordifolia): It is often used in the treatment of uterine and ovarian cancer. The Rubia cordifolia extract has shown a mitodepressive effect on the rate of cell division in bone marrow cells of Swiss male mice. This reduction in cell division process occurs due to inhibition of protein synthesis, suggesting probable effect of Rubia extract on the biosynthesis of certain amino acids as well as RNA synthesis. RC-18, a compound isolated from Rubia cordifolia, has shown promising results against many experimental tumors.
Ashwagandha (Withania somnifera): The alcoholic extract of the dried roots of this plant have shown significant antitumor activity on experimental tumors in vivo, without systemic toxicity. Many studies indicate that Withania somnifera could stimulate the generation of cytotoxic T lymphocyte and it may reduce tumor growth.
Madagascan Periwinkle (Vinca roseus): Catharanthus roseus L (apocyanaceae) also known as Vinca Rosea, has more than 400 known alkaloids, some of which are approved as anti-neoplastic agents to treat leukemia, Hodgkin’s disease, malignant lymphomas, neurobl astoma, rhabdomyosarcoma, Wilms’ tumor, and other cancers. The young leaves of this plant are used to produce the anti-cancer drugs vincristine and vinblastine. These drugs help to treat leukemia and lymphoma.
Shatavari (Asparagus racemosus): It has also been found to possess anti- carcinogenic activity. Chloroform/ methanol (1:1) extract of fresh root of A. racemosus reduces the tumor incidence in female rats treated with DMBA (7,12 dimethyl benz(a) anthracene). This action is possibly due to mammotropic and/or lactogenic influence of A. racemosus on normal as well as estrogen-primed animals, which renders the mammary epithelium refractory to the carcinogen. Several other studies have also demonstrated anti-cancer properties of this herb.
Brahmi (Bacopa monniera): Anti-cancer properties of Brahmi have been well established by several studies undertaken by Bhakuni et al and Elangovan V. et al.
A good diet can boost the immune system thus aiding in the fight against cancer. Therefore, cancer patients need to take special care of including healthy ingredients in their diet.
Low sugar diets seem to starve cancer cells, as they seem to use sugar as their basic fuel. In addition, a high sugar intake increases conditions like acidosis, immune system suppression and prostaglandin production, all of which encourage the growth of cancer cells. On the other hand, a diet rich in fruits and vegetables could keep away cancer. Fruits and vegetables contain many phytochemicals that can reduce the incidence of many cancers. These include cauliflower, tomatoes, soybeans, citrus fruits etc. Use of buttermilk can clean the body by helping indigestion.
Nutritional benefits of some foodstuffs that can aid in the fight against cancer are:
Green Tea: Green tea has strong free radical scavenging properties. It is thought to reduce the incidence of cancer of pancreas, stomach, colon, breast and lung. Based on a Chinese study, cancer rates sharply decrease with increased green tea consumption. A study in Japan has also shown that green tea reduces metastasis in breast cancer patients and improves prognosis. Green tea catechins (GTCs) have shown to be effective in inhibiting prostate cancer. The epidemiological data indicates that consumption of five or more cups of green tea per day is useful in the prevention of breast cancer development. It is also indicated that green tea consumption may help in
Soybean: Isoflavones found in soybean have several anti-cancer properties, like inducing apoptosis in cancer cells, slowing down their DNA synthesis and cell division, etc. Isoflavones probably stimulate genetic changes, converting cancer cells back into non-cancerous cells.
Agaricus, Aloe vera, Chlorella: These plants can boost the immune system. Mushroom extracts are found to be successful in reversing cancer growth. Studies suggest that under certain conditions, these mushrooms exhibit anti-mutagenic activities. Aloe- emodin (AE), a compound present in Aloe vera leaves, has a specific in vitro and in vivo anti-neuroectodermal tumor activity. A compound named ‘aloin’ from Aloe vera has been tested on human uterine carcinoma HeLaS3 cells. It showed a pronounced antiproliferative effect at physiological concentration, caused cell cycle arrest in the S phase and markedly increased HeLaS3 cell apoptosis.
Similarly, an active substance with anti-tumor activity (ARS2) has been isolated from the culture media of Chlorella vulgaris (single-cell algae). When a hot water extract of the algae was injected into the peritoneal cavity of mice inoculated with tumour cells, the survival times were strikingly prolonged. It has also been found that the administration of Chlorella is useful in preventing gastrointestinal absorption of dioxin (a known carcinogen) and in promoting the excretion of dioxin already absorbed into tissues.
Wheat grass: Wheat grass has 60 times more vitamin C than citrus fruits and contains more than 100 vitamins, minerals, and nutrients; all eight essential amino acids; and many bioflavonoids. Bioflavonoids are a group of more than 4,000 naturally occurring phenolic compounds that act as antioxidants. Wheat grass is believed to help in detoxifying the body and strengthening the immune system.
Antioxidants: Many studies have revealed that individual antioxidants such as vitamin A, vitamin E, vitamin C and carotenoids induce cell differentiation and growth inhibition in cancer cells. The proposed mechanisms for these effects include inhibition of protein kinase C activity, prostaglandin El-stimulated adenylate cyclase activity, expression of c-myc, H- ras, and a transcription factor (E2F), and induction of transforming growth factor-ß and p21 genes. These vitamins also reduce the toxicity of many standard cancer therapeutic drugs on normal cells.
Low fat and high fibre diets can further enhance the efficacy of standard cancer medicines. The proposed mechanisms for these effects include the production of increased levels of butyric acid and binding of potential mutagens in the gastrointestinal tract by high fibre and reduced levels of growth promoting agents such as prostaglandins. Hence, multiple antioxidant vitamin supplements significantly improve the efficacy of standard and experimental cancer therapies.
D-limonene: It is a compound (a terpene), found in the oil derived from orange peels. The d-limonene and its metabolites exert chemopreventive and chemotherapeutic activities against different tumors as shown by studies in animal models and clinical trials. Researchers at the University of Wisconsin have observed that when d-limonene was added to the diets of rats with developed tumours, 90% of these tumours disappeared completely. D-limonene has well-established chemopreventive activity against many types of cancers. A phase I clinical trial shows a partial response in a patient with breast cancer and stable disease for more than six months in three patients with colorectal cancer.
Garlic: Many studies have shown that the organic ingredient of garlic, allyl sulfur, is effective in inhibiting or preventing cancer of colon, prostate and stomach. It may also help restore natural killer (NK) cell activity. Aged garlic extract (AGE) may protect intestinal damage caused by anti-tumour drugs like methotrexate (MTX) and 5- fluorouracil (5-FU) in rats. Also, a lectin prepared from garlic can strongly reduce the growth and DNA synthesis of human tumour cells in a time- and dose-dependent manner. This lectin also induces apoptosis in cells at a low concentration. In another study, it has been revealed that cell differentiation and suppression of tumorigenicity were significantly induced in tumour cells after garlic oil treatment. Results suggested that tumour suppressor gene waf1 / p21 and wt p53 might play an important role in this effect.
Rice bran: Inositol, which is a natural phytochemical found in rice bran, increases the Natural Killer (NK) cell activity, thus exhibiting anti-tumour activity. Rice bran saccharide (RBS), a polysaccharide contained in rice bran, shows anti-tumour properties. In a study on tumour prevention and suppression of tumour growth in rats, RBS has been shown to suppress carcinogenesis.
Psychosocial care is increasingly recognized as an essential component of the comprehensive care of an individual with cancer. Psychological counseling, support groups and psychotherapy are important parts of cancer therapy. Music, meditation, relaxation techniques, and stress reduction result in significant improvement of body systems. Studies have indicated that positive thinking activates the immune system and supports healing.
Visualization: It is the process of imagination of the healing process. Many therapists believe that there is a strong connection between mind and body. Our thinking greatly affects our physiology, including our immune system. If a patient is optimistic and expecting a positive outcome, chances of survival and healing are increased. So patients are expected to strongly visualize that they would be cured completely.
BROCCOLI FIGHTS CANCER
BROCCOLI, a vegetable belonging to the Brassicacea family has proved to be a potent shield against cancer as it is rich in antioxidants like polyphenols. Besides, the unique anti-cancer and other medicinal properties, it is also rich in various health promoting nutrients like vitamin C. One hundred grams of broccoli contains enough vitamin C to meet the daily requirement of an adult person.
The name “broccoli” has been derived from the Italian word “brocco” meaning “a shoot”. The plant forms a kind of head, consisting of green buds and thick fleshy flower stalks, which can be consumed by boiling or steaming. Some other important cultivar groups of Brassica oleracea are cabbage, cauliflower and Brussels sprouts.
This cool-weather crop is rich in vitamin C, folic acid and soluble dietary fibres. It contains a number of nutrients with potent anti-cancer properties, including diindolyl methane and selenium. Particularly, 3,3′ – diindolyl methane is an active modulator of the innate immune response system with antiviral, anti-bacterial and anti-cancer activities.
Like other Brassica vegetables, broccoli is also rich in glucosinolates, which are metabolized to cancer preventive substances like isothiocyanates. Glucoraphanin, a compound present in broccoli, can be processed into sulphoraphane, a known anti-cancer agent. Broccoli leaf is edible and contains a lot of beta-carotene. Therefore, a high intake of broccoli has been found to reduce the risk of many types of cancer, especially prostate cancer.
Methods of storage and cooking have varying impacts on anticancer effects of broccoli. Domestic storage of the vegetable at ambient temperature in a refrigerator shows only minor loss of glucosinolate levels over seven days. However, when stored at a much lower temperature the loss may be up to 33% by fracture of vegetable material during thawing. On the other hand, a total loss of 77% glucosinolate has been observed after boiling it for 30 minutes.
Exercise: Exercise is very beneficial in cancer therapy. Those who exercise, work, or play can have better outcome than those who stay in bed. Studies have shown that exercise significantly reduces a woman’s risk of developing breast cancer.
Homeopathy: Although it is an effective therapy, large double blind clinical trials are needed to prove that homeopathy is useful in cancer treatment.
In a nutshell, an integrative treatment approach certainly helps a cancer patient to put up a brave fight against the disease.
VERSATILE VITAMIN C
FOUND in plenty in citrus fruits, green vegetables, tomatoes, germinated grams, dry fruits and milk, vitamin C or ascorbic acid is a water- soluble vitamin with a simple molecular structure. First isolated by Albert Szent-Gyorgyi in 1928, the structure of vitamin C was determined by Hirst Haworth. Haworth and Szent- Gyorgyi, who described the anti-scurvy activity of vitamin C, were awarded the Nobel Prize in 1937. However, C.G. King and W.A. Waugh I in 1 932 for the first time isolated vitamin C in pure crystalline form from lemon ^^^^ juice.
Although vitamin C is widely distributed in the animal and plant kingdoms, human beings are unable to naturally synthesize it in the body, due to the lack of a liver enzyme, L- gulono-a-lactone oxidase. This vitamin is well known for the treatment and prevention of scurvy – a disease characterized by anemia, alteration of protein metabolism and weakening of collagenous structures in bone, cartilage, teeth and connective tissues.
Vitamin C is also useful in preventing haemorrhagic disorders, infectious diseases, gastro-intestinal disturbances, cystine stone formation and neurolathyrism. It also plays several important roles in the functioning of the brain, effectively ameliorates many allergic responses, and stimulates the immune system. The daily requirement of vitamin C is 10 to 30 milligrams. Deficiency symptoms develop after 4 to 6 weeks as the body uses the stored vitamin.
As vitamin C is concentrated in the adrenal gland, especially in periods of stress, it is believed to be required for the hydroxylation reactions involved in the synthesis of some corticosteroids. It protects vitamin A, vitamin E, and some B vitamins from oxidation and enhances the utilization of folic acid by aiding the conversion of folate to H4 folate or by the formation of polyglutamate derivatives of H4 folate.
The role of vitamin C in potentiating multiple aspects of human resistance to cancer is not new. As vitamin C is an antioxidant, it helps in scavenging free radicals responsible for the development of cancer. It plays an important role in anti-cancer defence mechanism in the following ways:
- Prevents the formation of nitrosamines (a potent carcinogen) from nitrites and amines.
- Intake of foods rich in vitamin C like lettuce is known to decrease the incidence of human gastric cancer.
- Protects the body against human bladder cancer and destroys a potent bladder carcinogen called N-methyl- N-nitrosoguanidine.
- Needed to produce collagen, which protects the body by forming a wall around cancerous tissues.
- May inhibit the spread of cancer by neutralizing an enzyme (hyaluronidase) that catalyzes reactions for cancer metastasis.
- Neutralizes the toxic carcinogens contained in cigarette smoke.
- Can reverse the carcinogenic effect of ultraviolet light.
CHILDREN are beautiful of Nature. Sheer neglect of hygiene in the early days of life can play havoc in the infant body, letting germs of a wide variety make home in the tiny organs playing a dangerous game of life and death. The aftermath of an infectious childhood illness is most appalling if survival is at the cost of living with a crippled body for whole life. This exactly happens when the deadly virus, known to cause polio, strikes!
One of the most dreaded childhood diseases, polio mostly strikes children under five years of age. What saddens most is that despite the availability of time-tested vaccines and global efforts in full swing to eradicate this disease, polio still incapacitates innocent, young lives in a few parts of the world that includes India.
The crippling effects of polio have been known since ancient times. Egyptian paintings and carvings clearly depict people with droopy limbs and children walking with canes. An English physiciari, Michael Underwood in 1789 gave the first clinical description on polio as a debility of the lower extremities’. Due to the work of physicians, Jakob Heine in 1840 and Karl Oskar Medin in 1890, polio was also known as Heine-Medin disease. ‘Infantile paralysis’ is yet another name for polio as it primarily affects children’s.
Although polio was well recognized as a human affliction for long, it was only in 1908 that the culprit bug for this disease, the polio virus, was identified by Karl Landsteiner. Polio spread widely in Europe and the United States in late 1880s and as the virus circulated rampantly around the globe, polio cases dramatically increased. It was in the face of such epidemics in early 1900s, paralyzing primarily the young, that serious work on developing a potent polio vaccine began. Jonas Salk first developed a polio vaccine in 1952, and a decade later, Albert Sabin designed yet another vaccine to combat polio. No doubt, these potent protective tools have helped in reducing the global burden of polio as the number of polio cases, per year, have significantly lessened over the years.
The Polio Virus
The polio virus belongs to the genus enterovirus, which is a group of RNA viruses that make home in the human gastrointestinal tract. The basic structure of this virus is very simple as it comprises a single strand of RNA enclosed in a protein shell called the capsid. Besides protecti genetic material of poliovirus, the capsid proteins enable this virus to infect certain types of cells.
Three different serotypes of polio virus are known to cause the disease -poliovirus type 1 (PV1), type 2 (PV2), and type 3 (PV3) – each having a slightly different capsid protein. Although all these viral serotypes are extremely dangerous and result in the same disease symptoms, PV1 is most closely associated with paralysis.
From Infection to Paralysis
Polio is an acute viral disease. The word ‘poliomyelitis’ is derived from the Greek polios that means ‘grey’ and myelos referring to the ‘spinal cord’, while the suffix -it is, denotes inflammation. This disease is highly infectious as it spreads through the fecal-oral route, and thus, gets transmitted through contaminated food and water in mainly places with poor sanitation facilities. The virus particles start getting excreted in the feces for several weeks following initial infection, which is the most infective stage as the virus quickly spreads from one to more hosts, especially in areas endemic to the virus. Sometimes, the virus also gets transmitted via the oral-oral route. Thus, transmission of polio virus occurs if the virus is present in the saliva or feces. The incubation period, which is the time between the first exposure and appearance of first symptoms, is normally 6 to 20 days.
As the polio virus enters the body through the mouth, it infects the cells lining the throat and intestine. Interestingly, the polio virus gains cellular entry by binding to special receptors, which are proteins sitting on the surface of host cells. The virus then hijacks the machinery of the host cell and begins to replicate furiously. The initial symptoms of polio infection include sore throat, fever, fatigue, headache, vomiting, stiffness in the neck, abdominal pain and pain in the limbs. In about 90% of cases, however, there are no perceptible symptoms, but the polio virus is excreted in the faeces, which is why the spread of infection by such cases is very high.
After dividing within gastrointestinal cells for about a week, the polio virus spreads to the tonsils (specifically the follicular dendritic cells), the intestinal lymphoid tissue (M cells of Peyer’s patches), and other lymph nodes. Soon the virus gets absorbed into the bloodstream. This stage when the polio virus appears in the bloodstream and starts its journey of spreading across the whole body is called viremia. The polio virus is able to survive and multiply within blood and lymphatics for periods as long as 17 weeks, which leads to the development of minor influenza-like symptoms. Patients with abortive polio infection recover completely.
In rare cases though, about 3% of infections, the virus chooses to invade the central nervous system (CNS). Why the polio virus diverts its attention from gastrointestinal tract to causing infection in the parts of CNS is, however, not fully understood, though it appears to be only a chance event. Most patients with CNS involvement develop non-paralytic aseptic meningitis, which is the inflammation of meanings-the layers of tissue surrounding the brain. The symptoms last for 2 to 10 days, followed by complete recovery. On an average, 1 in 200 of such cases progress to paralytic disease, as the virus attacks the nerve cells that control muscle movement, due to which the muscles become weak, floppy and poorly controlled, and finally completely paralyzed-a condition known as acute flaccid paralysis. This is the most horrific form of polio as the patient is reduced to a pathetic figure of constant suffering.
A hapless 1% of polio cases are those where the virus spreads along certain nerve fibre pathways, mainly destroying the motor neurons within the spinal cord, brain stem, or motor cortex, which leads to the development of paralytic poliomyelitis. Different types of paralysis may occur, depending on the nerves involved.
Although the molecular mechanisms of paralytic polio needs to be understood more clearly, there visibly occur various lesions/cellular abnormalities within the spinal ganglia as these nerve cells get destroyed by the invasion of polio virus. The inflammation associated with nerve cell destruction often alters the colour and appearance of the gray matter in the spinal region, causing it to appear reddish and swollen. Other destructive changes associated with paralytic polio occur in the hypothalamus and thalamus regions of the brain.
Early symptoms of paralytic polio include high fever, headache, difficulty in swallowing, stiffness in the back and neck, asymmetrical weakness of various muscles, loss of reflexes and sensitivity to touch. Paralysis generally develops between 1 to 10 days after early symptoms begin, which progresses for two to three days, and is complete thereafter. The chances of developing paralytic polio increase with age. In children non-paralytic meningitis occurs commonly if the polio virus infects the central nervous system, and paralysis occurs in only 1 in 1000 cases, while In adults, paralysis occurs in 1 in 75 cases. In children under five years of age, paralysis of one leg is most common; whereas in adults, extensive paralysis of the chest and abdomen also affecting all four limbs- quadriplegia- commonly occurs. Moreover, if infection is with poliovirus type 1, then paralysis rates are highest while the rate of occurrence of paralysis is lowest with type 2 polio virus.
Spinal polio is the most common form of paralytic polio. It occurs when the polio virus invades the motor neurons of the anterior horn cells, or the front gray matter in the spinal column, which are responsible for movement of the muscles located in the trunk, limbs and the intercostal muscles. Basically, there occurs inflammation of the nerve cells, leading to damage of motor neuron ganglia. Innervated by the dead neurons, the muscle tissue now no longer receives signals from the brain or spinal cord, which is why the affected muscles become weak. A continuous lack of nerve stimulation, slowly leads to muscle atrophy that is manifested as poorly controlled, floppy muscles and ultimately, complete paralysis. Progression to paralysis is rapid as it occurs within two to four days, and is usually associated with fever and muscle pain.
The extent of spinal paralysis, however, depends on the region of the cord affected. Although any limb or combination of limbs may be affected, paralysis is mostly asymmetrical as the virus normally affects muscles on one side of the body. If the affected nerve cells are completely destroyed, paralysis is permanent, while cells that simply lose function temporarily recover within four to six weeks. Half the patients with spinal polio recover fully, one quarter recover with mild disability and the remaining quarter are left with severe disability.
About 2% of cases of paralytic polio are bulbar polio, where the polio virus invades and destroys nerves within the bulbar region of the brain stem, which is the region of white matter that connects the cerebral cortex to the brain stem. The destruction of nerves in this region weakens the muscles, which are stimulated by cranial nerves, thus resulting in symptoms of encephalitis, besides causing difficulty in breathing, speaking and swallowing. The set of nerves that are affected in bulbar polio comprise the ‘glossopharyngeal’ nerve, which partially controls swallowing and functions in the throat, tongue movement, and taste; the ‘vagus’ nerve, which sends signals to the heart, intestines, and lungs; and the ‘accessory’ nerve, which controls upper neck movement. Besides, there occurs facial weakness caused by the destruction of ‘trigeminal’ nerve and ‘facial’ nerve, which innervate the cheeks, tear ducts, gums, and muscles of the face. Respiratory difficulties also arise, which may be fatal.
About 19% of all paralytic polio cases have both bulbar and spinal symptoms, where the polio virus affects the upper part of the spinal cord, as well as the diaphragm. The nerves affected are the ‘phrenic’ nerve, which controls the movement of diaphragm during the process of breathing, as well as nerves that drive the muscles needed for swallowing. Destruction of these nerves affects breathing, making it difficult for the patient to breathe without the support of a ventilator. It also leads to paralysis of the arms and legs and may even affect heart functions. Overall, 5-10% of patients with paralytic polio die due to the paralysis of muscles used for breathing.
Cases showing acute onset of flaccid paralysis, with decreased or absent tendon reflexes in one or more limbs, are suspected to progress to complete paralytic poliomyelitis. A laboratory diagnosis is usually made by the detection of polio virus from the stool sample or a throat swab sample. Analysis of the patient’s cerebrospinal fluid (CSF), collected by lumbar puncture, also reveals an increased number of lymphocytes (white blood cells). Detection of virus in the CSF is diagnostic of paralytic polio. Once the polio virus is detected in the patient, the DNA-based PCR (Polymerase Chain Reaction) test could be employed to confirm the type of the infecting polio virus. If the source of a reported case of paralytic polio is some wild strain of the virus, then it is estimated that about 200 to 3,000 infectious asymptomatic carriers may be present in that population.
On exposure to the polio virus, either by natural infection or by vaccination, the immune system gets into gear resulting in the production of antibodies, namely immunoglobulins A (IgA) against the virus that blocks viral replication. Subsequently, other special immunoglobulins are produced (IgG and IgM) that prevent the spread of the polio virus to motor neurons of the CNS. However, an exposure to one serotype of poliovirus does not provide immunity against the other serotypes, which means that to acquire immunity against all the serotypes exposure to each serotype is required.
The idea for this approach, to prevent polio, was put forth by William Hammon of the University of Pittsburgh in 1950, who purified antibodies to poliovirus from the blood plasma of polio survivors. In a clinical trial, the use of protective antibodies was shown to be about 80% effective in preventing the development of paralytic poliomyelitis, while reducing the severity of polio in those infected by the virus. This approach, however, had its limitation of large-scale production, which thus paved the way for designing polio vaccines.
There are basically two vaccines, used throughout the world, for combating polio. Both vaccines induce active immunity to polio, and blocks person- to-person transmission of the wild polio virus. The first polio vaccine was developed in 1952 by Jonas Salk, which comprised the killed or inactivated polio virus (IPV). Popularly called the Salk vaccine, it is based on growing the polio virus, of all three serotypes, in a type of monkey kidney tissue culture (Vero cell line), which is chemically inactivated using formalin. Two doses of IPV (given by injection), helps to develop protective antibodies to all the three serotypes of polio virus in about 90% of vaccinated individuals while three doses of this vaccine provide protective immunity to 99% of the recipients.
Albert Sabin developed an oral polio vaccine (OPV) using live but weakened (attenuated) polio virus, that was produced by the repeated passage of this virus through non-human cells grown at specific temperatures. Sabin vaccine was ready for human trials in 1957 and was finally licensed in 1962. This weakened form of polio virus replicates very efficiently in the gut, which is the primary site of wild polio virus infection. A single dose of OPV produces immunity to all three polio virus serotypes in about 50% of recipients, while three doses of this live-attenuated vaccine produce protective antibody to all three poliovirus types in more than 95% of recipients. Besides, OPV is inexpensive, easy to administer, and produces good gut immunity which is why this has been the vaccine of choice for controlling polio in many countries. Unfortunately, however, in about 1 case per 750,000 vaccine recipients, the attenuated virus in OPV reverts into a virulent form that can cause paralysis. Therefore, many countries have switched to IPV, where the virus is killed and cannot revert, either as the sole vaccine against polio or in combination with OPV.
Many cases of poliomyelitis result in only temporary paralysis. Nerve impulses resume normal function within a month with complete recovery in six to eight months. However, body parts that remain paralyzed for more than a year do not mostly recover their muscle strength. Therefore, once the virus has completely damaged the specific motor nerves, there is no going back and the victim has to live with paralyzed body parts. In other words, there is no cure for polio.
The focus of modern treatment is basically on providing relief of symptoms. While antibiotics come to the rescue to prevent infections in the weakened muscles, analgesics help to relieve pain, and long-term rehabilitation involves the use of braces, corrective shoes and also orthopedic surgery in some cases. Besides, moderate exercise and a nutritious diet play a key role in providing victims the strength to carry on with the daily chores of life.
Some victims, with permanent respiratory paralysis, require ventilators to support breathing. Modern portable ventilators help such victims to survive. Some age-old treatments for improving the life of paralytic polio cases include water therapy, electrotherapy, massage and even surgical treatments like tendon lengthening and nerve grafting.
Road to Recovery
Once polio infection has been checked, the body’s inherent recovery processes take over and facilitate the restoration of muscle functioning of the affected parts. One such process is nerve terminal sprouting, by which the normal motor neurons of the brainstem and spinal cord develop new branches or sprouts that reinnervate those muscle fibers whose motor neurons were damaged by acute polio infection, thus improving the strength of such fibres. Through terminal sprouting, a single motor neuron that earlier controlled 200 muscle cells might control 800 to 1000 cells. Muscle strength restoration also occurs by myofiber hypertrophy, which is the enlargement of muscle fibers through proper exercises. Besides, the body naturally begins to use weaker muscles at a higher than normal capacity of that muscle.
Despite the body’s inherent processes working in full swing to bring back strength to damaged muscles post polio infection, several movement disabilities may take root in the body due to skeletal deformities and tightening of the joints. For example, ‘equinus foot’ is a deformity that develops when the muscles that pull the toes downward are working, but those that pull it upward are not, and the foot naturally tends to drop towards the ground. If left untreated, the Achilles tendons at the back of the foot retract and the foot cannot take on a normal position. Polio victims that develop this condition cannot walk properly because they cannot put their heel on the ground.
Another common deformity arises when the growth of an affected leg is slowed by polio, while the other leg continues to grow normally. This makes one leg shorter than the other, due to which the person limps and leans to one side that in turn leading to deformities of the spine. Other disturbing complications include osteoporosis that increases the chance of bone fractures, extended use of braces or wheelchairs resulting in loss of proper function of the veins in lower limbs, besides scores of medical problems involving the lungs, kidneys and heart that arise due to extended immobility of body parts. Several polio victims who have survived an attack of paralytic polio in childhood develop additional symptoms, like muscle weakness and extreme fatigue, decades after recovering from the acute infection. Called ‘post-polio syndrome’, it occurs due to both overuse and disuse of existing motor neurons.
Global Polio Eradication
In 1988, the World Health Assembly, comprising delegates from 166 Member States, adopted a resolution for the worldwide eradication of polio. It marked the launch of the ‘Global Polio Eradication Initiative’, spearheaded by the World Health Organization (WHO), Rotary International, the US Centres for Disease Control and Prevention (CDC) and UNICEF. It is the largest public health project in the world, which is tirelessly working to ensure that no child ever comes under the crippling effects of polio. It is heartening that this Project has resulted in reducing the globally estimated 3.5 lakh cases in 1988 to 1310 cases in 2007.
Improvements in community sanitation like better sewage disposal and supply of clean drinking water have reduced childhood exposure to polio virus in many regions of the world. Thanks to the widespread use of polio vaccine since the mid-1950s, the incidence of this disease has dramatically declined in the developed world and many countries have been even certified polio-free. For example, the US was declared polio-free in 1994, while in 2000 polio was officially eradicated in 36 Western Pacific countries, including China and Australia. Europe was declared polio- free in 2002. However, between 2003 and 2005, 25 previously polio-free countries were re-infected due to transport of the virus. This only proves the point that even if a single child remains infected, children in all countries are at risk of contracting polio.
Today polio mainly afflicts people in Asia and Northern Africa. As of 2006, polio remains endemic in parts of only four countries: Nigeria, India (mainly Uttar Pradesh and Bihar), Pakistan, and Afghanistan. The thrust of current efforts to eradicate polio is on strengthening the routine immunization systems and surveillance for communicable diseases in polio-affected nations.
The four core strategies to stop transmission of the wild polio virus in such areas include high infant immunization coverage with four doses of OPV in the first year of life; supplementary doses of OPV to all children under five years of age; surveillance for wild polio virus through reporting and laboratory testing of all acute flaccid paralysis (AFP) cases among children under 15 years of age; and targeted ‘mop-up’ campaigns once wild polio virus transmission has been limited to a specific area.
Needless to say, the key to stopping wild polio virus transmission in endemic countries is the presence of a high level of political commitment at National, State and District levels. In 2007 an intensified effort to eradicate polio was initiated in all these four countries, with focus on new monovalent vaccines and diagnostics that are more effective in detecting and stopping polio transmission.
A country is certified polio-free if it satisfies three conditions: First, there are no polio cases due to wild polio virus since at least three years; Second, disease surveillance efforts of the region meet international standards; and third, the country illustrates the capacity to detect, report and respond to ‘imported’ polio cases. Finally, for the world to be certified polio-free, it is pertinent that laboratory stocks are contained and safe management of the wild virus in polio vaccine manufacturing sites is assured.
Polio in India
It is unfortunate that in 2009 India has earned the dubious distinction of reporting the highest number of polio cases in the world. According to data from the Global Polio Eradication Initiative, India reported 624 polio cases in 2009 compared to 559 polio cases reported from the country in 2008. Another high burden country, Nigeria, reported 383 polio cases in 2009 and 798 cases in 2008.
In India, vaccination against polio was initiated in 1978 under the Expanded Programme on Immunization (EPI) and the coverage achieved by 1984 was around 40% of all infants with three doses of OPV. In 1985 the Universal Immunization Programme (UIP) was launched that covered all districts in the country by 1989-90. According to the Indian Academy of Pediatrics, a total of five polio doses need to be administered in the first year of life, under the routine polio immunization.
The number of reported cases of polio declined from 28757 during 1987 to 3265 in 1995. Besides a number of initiatives have been implemented in India to intensify efforts to stop the transmission of wild poliovirus. These include widespread advocacy efforts, introduction of monovalent oral polio vaccine (mOPV1) in high-risk areas and expanding the reach of immunization campaigns.
In addition to routine immunization, the Pulse Polio Immunization Programme was launched in 1995-96 that consisted of administering OPV to children, under three years of age, at fixed booths on select National Immunization Days. In order to reach the global goal of being polio free, the pulse polio drive was later intensified with multiple nationwide rounds of polio immunization and sub-national rounds in Assam, Bihar, Gujarat, Madhya Pradesh, Orissa, Rajasthan, Uttar Pradesh and West Bengal in addition to routine immunization, covering all children under the age of 5 years. In addition to booth immunization, a house-to-house search of missed children and vaccinating them on the next 2-3 days following the pulse polio day was also started to further increase the immunization coverage.
Wiping out an age-old disease from the face of the Earth that houses more than 6.5 billion people is not easy. Although it poses a difficult challenge, it is not insurmountable. The current, concerted global efforts to combat polio are indeed praiseworthy. It surely seems that the day, when human populations will awake to a polio free world, would dawn sooner than later.
JUST imagine the human body without the in and out rhythmic flow of breath. It is only at death that the breath and the body separate. It is this constant alternate breathing in of oxygen and breathing out of carbon dioxide that keeps us alive. But this process of breathing is compromised in about 300 million people worldwide who suffer from asthma, as the flow of air through their lungs is obstructed.
The inhaled oxygen reaches the lung through the windpipe/trachea, which divides into two large tubes or bronchi, one for each lung. Each bronchus further divides into millions of thin, tiny air passages called bronchial tubes through which the inhaled oxygen passes before it reaches the round structures, present at their tips, called the air sacs or alveoli. These airways become smaller and narrower as they get deeper into the lungs, just like the branches of a tree that are smaller and narrower than the tree trunk. It is in the alveoli that the exchange of gases occurs, as the inhaled oxygen gets into our bloodstream through the rich capillary network surrounding the alveoli, while carbon dioxide – a by-product of cellular metabolism – passes into the air passages, through the capillary network around alveoli, to be exhaled out through the nostrils.
In people with asthma, the airways are blocked, which is why they suffer from laboured breathing that is often accompanied by coughing, chest tightness and wheezing during an asthma attack. It is unfortunate that many victims of asthma are children and young adults.
The blocking of airways primarily occurs due to three reasons: swelling of the airways, called, inflammation’; squeezing of the airways called bronchoconstriction’, and plugging up of the airways with mycus.
Swelling: The swelling inside the airways is due to an inflammatory reaction that narrows down the space where the air flows. People who have persistent asthma have a mild swelling in the airways at all times, even when such people are apparently breathing well. Therefore, they have ‘sensitive’ lungs, and in presence of a slight trigger their airways swell more resulting in an asthma attack. In essence, asthma is the result of an immune response in the bronchial airways.
Squeezing: All airways in the lungs have little muscles wrapped around them. During an asthma attack, these tiny muscles get tighter squeezing the airways, almost closing them completely and seriously obstructing the movement of air. Also known as ‘bronchoconstriction’, it usually happens very fast and results in wheezing that indicates tightness in the chest.
Mucous plugging: Normally some mucus is always made inside the airways. But in people having asthma, the airways produce more mucus, which is also thicker than the normal mucus. Therefore, if the airways are already small due to inflammation and bronchoconstriction, the extra mucus can plug them up completely making breathing very difficult. Many asthma victims cough up mucus during an attack.
Asthma exists in two states: the steady-state of chronic asthma, and the acute state. The common symptoms of asthma in a steady-state include: night- time coughing, shortness of breath with exertion, a chronic ‘throat-clearing’ type cough, and complaints of a tight feeling in the chest.
In an acute asthma attack, the person suffers from shortness of breath, wheezing, and chest tightness. The onset may be sudden, with a sense of constriction in the chest, as breathing becomes difficult and wheezing occurs, making it difficult to even talk. As exhaling through the obstructed airways is difficult, too much stale air remains in the lungs after each breath. This results in high concentration of carbon dioxide in the lungs making the blood more acidic, which may rise to toxic levels if asthma remains untreated.
During very severe attacks, an asthma victim can turn blue from lack of oxygen, feel numbness in the limbs with sweating of palms, experience chest pain and even become unconscious. If uncontrolled, the symptoms of severe asthma can further aggravate and the attack can become life-threatening, leading to respiratory arrest and death.
VACCINES PREPARATION AND TYPES
Vaccines are manufactured biological preparations. Vaccines help the immune system learn to resist a specific disease by exposing it to germs that are weak or dead, or to materials that resemble parts of harmful germs.
The vaccine preparation must be either killed or attenuated. Attenuated means the vaccine organism is modified so it no longer causes disease. Killed and modified live vaccines are the most common types of vaccines. Killed vaccines are made by growing the virus or bacteria, then inactivating or killing the organisms using either heat or chemical.
Modified live vaccines are made from an isolate of virus or bacteria. The virus has been attenuated. Attenuated means the virus cannot cause disease but it can reproduce in the body cells and stimulate immunity. Killed vaccines may be killed viruses; killed bacteria called bacterins, or killed toxins called toxoids. Vaccines are tested for sterility before they are released for sale. Vaccines generally must be stored in cooler temperatures to maintain potency.
Vaccines might even help people who have already been infected with HIV, by restoring and strengthening immune responses. This approach is still being researched.