Archive for July, 2008

Effects of Air Pollution

More than one billion urban residents are exposed t air pollution level more than recommended. Air quality in industrialized countries have improved in last two decades but that of developing countries air quality has deteriorated due to increase in industrial activity without proper control and planning, increased power generation and congestion in streets with poorly maintained automobiles which are the main reason for air pollution. Air pollution affects mainly in two ways health aspect and economic and social aspect.

Health aspects: Health aspect of air pollution may be immediate and delayed. The immediate effects are seen mainly in respiratory system and commonest is acute bronchitis. In severest form of air pollution death can occur by suffocation. The best example of severe air pollution was seen in London in 1952.

The delayed effects of air pollution are also seen mainly in respiratory system which includes chronic bronchitis, lung cancer, bronchial asthma, respiratory allergies etc. Lead poisoning from air pollution can effect many systems of the body and is particularly dangerous in children during brain development and development of nervous system. Increase lead level in children results in lack of neuro psychological development measured by low IQ, poor performance in school and behavioral changes.

It is very difficult to estimate precisely the risk of air pollution for health. Degree of effect varies with factors such as nutrition, smoking, occupation and climate. Air pollution can damage cardiac and respiratory systems in many ways in old people & young, smokers and people with respiratory problems are more vulnerable to effects of air pollution. Epidemiological studies have shown that a sudden increase in air pollution level is associated with immediate increase in morbidity and mortality. It is assumed that achievable reduction in air pollution can prevent about 5% of all infections and respiratory problems. This reduction can reduce global burden of disease by more than 1%.

Social & economic aspects: These include destruction of plant and animal life, corrosion of metals, damage to buildings, increase cost of maintenance and cleaning. It can soil and damage clothing. It also reduces visibility in cities and affects air traffic in a big way.

Prevention & control of air Pollution: Control and prevention of air pollution is ultimately an engineering problem. WHO (World Health Organization) has recommended following ways to control and prevent air pollution:

1. Containment: This is prevention of escape of toxic substance into the air. This can be achieved by enclosures, ventilation, and air cleaning etc. Use of “arrester’s” is the latest development in the way of containment.
2. Dilution: It is useful to the extent that it is within the limit of self clearing of environment. Some of the air pollutants are removed by trees and green plants and vegetables. This is the idea of “green belts” between residential areas and industrial areas. But the capacity of dilution is limited as an effective way to control air pollution.
3. Replacement: This is the process of replacing older method by newer technology which causes lesser pollution. This is one of the most effective ways to control pollution. For examples increased use of electricity in stead of coal for heating has reduced amount of smoke. Another example is use of unleaded petrol instead of leaded petrol. Replacing petrol and diesel engines by natural gas is an effective way to reduce air pollution. Another example of replacement is to convert rail engines from coal or diesel engines to electric engines. Recently Airbus (aero plane manufacturing company) has conducted a test flight with biodiesel (which is obtained from oil sees instead of more polluting fossil fuel which contain more hydrocarbons).
4. Legislation: In many countries air pollution is controlled by suitable legislation. Legislation covers many areas like height of chimneys, distance between particular factories from residential areas, waste disposal. Power to local authorities to carry out investigation, research and education regarding pollution, enforcement of standard for air quality is given to the local authorities. Compulsory checking of automobiles for pollution checking is one of the ways to effectively control air pollution. There are pollution controlling boards or authorities formed by legislation to check & control pollution.
5. International action: WHO has set up an international network of laboratories for monitoring and air pollution. They include two international centers at London & Washington, three centers at Moscow, Tokyo and Nagpur (India) and twenty other laboratories in various parts of the world. These canters issue warning of air pollution when & where necessary.

Air pollutants: a Discussion

More than 100 substances has been identified which cause air pollution. The important air pollutants are discussed below; they are carbon dioxide, carbon monoxide, hydrogen sulphide, sulphur dioxide, sulphur trioxide, nitrogen oxides, organic campounds like hydrocarbons, ketones, aldehydes, flourine compounds, radio active compounds, ozone etc.

Air pollution is a serious problem in the modern time. Largest and most important cause of air pollution is burning of hydrocarbons by motor transport. The degree of air pollution, very from country to country and in a country from place to place. Unplanned urbanization also contributes to air pollution and air quality. Due to air pollution there is steady increase of average global temperature (global warming) and due to global warming serious natural calamities like draught & flood are taking place frequently.

Air pollutants may be in the form of gas, liquid or solid. The combination of smoke and fog is called “smog”.

Other containments of air include lead mercury, benzene, flourides, vinyl chloride etc.

1. Sulphur dioxide: This is one of the several forms of sulphur in air; others are hydrogen sulphide, sulphuric acid and salts of sulphur. This pollutant is produced when sulphur containing fossil fuel is burned, smelting of sulphur & from industries. Sulphur dioxide reacts with water and became sulphuric acid. 80?gm per cubic meter is considered the safe limit.
2. Carbon Monoxide: It is one of the most common air pollutants. It is a product of incomplete combustion (burning) of carbon containing materials, such as motor vehicle, heating facility, industrial process & power plants and industries. 350 to 600 million tones of carbon monoxide is produces every year by human activities mainly industries and automobiles. Some natural source of carbon monoxide producing places has also been identified. Carbon monoxide concentration depends on weather & traffic in cities. During rainy season its concentration is minimum and during winter its concentration is maximum. It also very with petrol powered vehicles in cities and morning & evening rush hours. Its concentration can be seen in blood as carboxy hemoglobin. Its concentration is expressed as 8 hours average concentration.
3. Hydrogen sulphide: In industries hydrogen sulphide is formed when sulphur come into contact with organic material at high temperature. It is produced in coke production plant, waste water treatment plant, wood pulp production unit, oil refining plant industry etc. If humans are exposed to more than 30?g per cubic meter concentration of hydrogen sulphide they suffer mental and neurological problems.
4. Carbon dioxide: It is a normal constituent of air. But when present in very high concentration it can produce adverse effect. It is produced during burning of coal, wood, gas, oil etc. Its concentration is alarmingly increasing and effectively increasing global temperature which is having its effect on climate change.
5. Lead: Man source of lead is lead content of petrol. So, in many countries now started producing unleaded petrol to reduce lead pollution, children & pregnant women are at higher risk of adverse effects of lead pollution due to ineffectiveness of placental barrier to prevent lead from going to fetus in pregnant women.
6. Hydro carbons: Its sources include incineration, combustion of coal, wood and use of petroleum. They take part in chemical reactions that causes photo chemical smog.
7. Ozone: It is one of the strongest oxidizing agents. It is formed by chemical reaction in air. It is combination of 3 (three) oxygen atoms in stead of two in normal oxygen. If excess ozone is present in air it causes oxidation of many materials. In the troposphere layer of atmosphere it is protecting earth from solar radiation by forming an ozone layer.
8. Particulate matters: These are complex mixture of organic and inorganic substances. They are divided in to two groups according to mass and composition. (a) Coarse particles larger than 2.5?m in aerodynamic diameter and (b) Fine particles smaller than 2.5?m in aerodynamic diameter. The fine particles are generally aerosols, combustion particles, organic and metal vapor. Large (coarse) particles are dust from roads, earth, and dust from industry. Respirable particles are emitted from power plants, automobiles, coal burning and incinerators. The sources are concentrated in urban areas. The maximum safe limit of suspended particulate matter (SPM) is 100?g per cubic meter.

Air pollution: An Open Discussion

The immediate environment of man comprises of air on which all the living beings depends. Air supplies the life giving oxygen and also serves several other functions. The body is cooled by air contact, the special senses of smell & hearing also acts through air. Many infections disease are spread through air. Air pollutants may cause sickness and death. The requirement of air per day is about 10 to 20 cubic meters for an adult.

Air is mechanical mixture of gases. The normal composition of air by volume is as follows: Nitrogen 78%, Oxygen 20.93%, Carbon dioxide 0.03%.The remaining is made up of other gases like argon, neon, krypton, xenon and helium. In addition to all the above gases air contains water vapor, traces of ammonia, and suspended matters like bacteria, dust, spores and vegetable debris.

Air becomes impure or polluted by following ways:

(1) Respiration of men and animals which consumes oxygen and release carbon dioxide.

(2) Combustion of coal, gas, oil etc.

(3) Decomposition of organic matter.

(4) Trade, traffic and manufacturing factories which emit dust, fumes, gases and vapor. Out of the above, maximum air pollution is caused by transport systems (motor vehicles, aero planes, trains & ships).

Generally composition of outdoor air is remarkably constant. This is due to presence of certain self cleansing mechanisms which are operational in nature. They are (1) Wind: Because of wind impurities do not accumulates in one place and they are diluted and swept away by wind. This is the reason housing should have proper ventilation system, so that impurities do not accumulate inside house and are swept away by wind. (2) Sunlight: Sunlight is very effective in killing & controlling bacteria in air, sunlight also oxidizes many impurities. (3)Rain: It cleans the atmosphere by removing impurities like dust, many gases and suspended particulate matters (SPM). (4 ) Plant life: The green plants uses carbon dioxide and produces/generate oxygen by photosynthesis, plant life also help by producing more rain to wash off pollutants.

Air in occupied room: Human occupancy and activity in an occupied room give a sense of discomfort to the occupants. Two types of changes occur in an occupied room, chemical and physical.

Chemical changes: As during respiration we take up oxygen & release carbon dioxide, in an occupied room air becomes progressively contaminated by carbon dioxide and oxygen content decreases. At rest an average person gives off 0.7 cubic feet of carbon dioxide every hour. This may go up to 2 cubic feet per hour during physical activity. In a mixed gathering, comprising of all age groups, the per capita carbon dioxide output is taken as o.6 cubic feet per hour. So in a crowded room oxygen concentration may reduce and carbon dioxide level increase and cause discomfort.

Physical changes: Physical changes are the most important changes that occurs in and occupied room. They are (a) Rise in temperature: The room temperature tends to rise due to emanation of body heat. A person at rest gives of about 400 BTU (British thermal unit) of heat per hour. One BTU is the amount of heat required to raise the temperature of one pound of water by 1 degree Fahrenheit. During physical activity the heat out put may by up to1400 BTU per hour.

Rise in humidity: Humidity inside an occupied room goes up due to evaporation of moisture from skin & lungs. The expired air contains about 6% of water vapor. An adult at rest release about 700gms of water vapor per day (24 hours), in the form of perspiration. It is calculated that an average person gives off 18.4gms of water vapor per hour during sleep and up to 175gms per hour during vigorous physical activity.

Decrease in air movement: In crowded rooms the natural movement of air is blocked.

Body odors: Unpleasant odors arise from perspiration, sweating, bad oral hygiene and bad breath, dirty cloths and other sources. This depends on social status, personal hygiene and age of people.

Bacterial pollutants: The exhaled air contains microorganisms (bacteria & virus). Some of these may be pathogen (can cause disease).These microorganisms are release during coughing, sneezing and talking.

So air in an occupied room should be replaced, otherwise it may have adverse effects on comfort, heath and efficient working. For these proper cross ventilation should be provided in every room.

Environment and Health: Broad Perspective

The study of disease is actually the study of human and his environment. The term environments include all the external factors living or nonliving, material or nonmaterial which surrounds human. But in modern definition of environment along with basic air, water and soil, it also includes social and economic conditions in which we live.

Environment is divided into three comportments and they are very closely related to each other.

(a) Physical: Air, water soil (earth), housing, wastes, radiation, heat, cold etc.

(b) Biologic: Plants & animals including bacteria, virus, fungus, insects algae etc.

(c) Social: Culture, customs & traditions, habit, occupation, religion etc.

The key to healthy life lies in the environment. Much of man’s ill health can be traced to his environment and its adverse effects on health like poor housing condition, high air pollution, water contamination and water pollution from factories, soil pollution insects & viruses.

The definition of sanitation as given by National Sanitation Foundation of USA as follows: “Sanitation is a way of life. It is the quality of living that is expressed in the clean house, the clean farm, the clean business, the clean neighborhood and the clean community”. Being way of life it must come from within the people. It is nourished by knowledge and grows as an obligation and an ideal in human relations.

In the past sanitation meant disposal of human excreta. In fact to many people sanitation still means disposal of excreta & construction of safe latrines .But in reality the term sanitation covers the whole field of controlling the environment with a view to prevent disease and promote health . Man already controls many factors in environment but his control is not complete. As old problems are solved new problems arises. Problems like air and water pollutions are serious problems at present. Solution of these is not in sight in near future.

The purpose of environmental health is to promote & maintain ecological conditions that will be better for health & prevent disease. At present more than one billion people lack safe drinking water & more than 2 billion people do not haw safe disposal systems of their excreta. In developing countries more than half of the OPD (out patient department) visits and hospital admissions are due to poor sanitation and environment. If environment can be protected & made better use of, the burden by community & nation due to sickness can be reduced drastically.

To achieve better health two things are required, healthy environment and healthy life style. For that, initiative is required by the individual in the family and in the community. A prgramme for hygiene education and low cost sanitation is being developed in Africa with the help of UNICEF and many other non government organizations.

Much of the ill health in developing nation is due to poor environmental sanitation, unsafe water, polluted soil, unhygienic disposal of human excreta and refuse, poor housing, insects and rodents.

The first step of any health programme is to eliminate through environmental control of the factors, which are harmful to health.

Unravelling Alzheimer’s Disease

Alzheimer’s disease is the most common form of dementia that makes people forget names, places and things and lose track of time and events irretrievably still remains a mystery. Science has so far failed to fully understand the exact cause of this brain disorder, let alone develop a cure. Alzheimer’s strike at old age and occasional memory lapse is the first symptom. The condition deteriorates rapidly and those suffering from its severest forms may not be able to recognize even their closest family members. Moreover, the patients often experience delusions and hallucinations.

The name “Alzheimer’s disease” entered the medical lexicon in 1907 following a description of the condition by the German physician Dr Alois Alzheimer at a scientific meeting the year before. Dr Azlheimer happened to treat a female patient in 1901, who had some peculiar symptoms like problems with memory, unfunded suspicions about her husband’s fidelity and difficulty in speaking and understanding what was said to her. After her death, which was about five years later, he performed an autopsy on her. He found that her brain had shrunken dramatically, particularly in the cortex region, the outer layer involved in memory, thinking, judgement and speech.

We still do not know the cause of the disease, but recent advances in neuro-imaging techniques have shown that those suffering from it have two abnormal structures in their brain: plaques formed of deposits of a sticky protein fragment called beta-amyloid, and tangled or twisted fibres of another protein called tau inside the dying neurons.

Most people develop plaques as they age, but those with Alzheimer’s tend to form them on a much larger scale and earlier than others. Ever since the discovery of these unusual elements in the brain of Alzheimer’s patients, scientists have been trying to find out what causes the trigger for their formation.

Recently published in an article of Nature Medicine, came up with an interesting finding. The scientists first isolated beta-amyloid from the brains of Alzheimer’s patients, and separated them as monomers, oligomers and insoluble plaque. They then injected these separately into the brains of mice. They found that memory was impaired only when soluble beta-amylid oligomers were administered the hippocampus (brain region where memory is stored) of the animals.

In an study by researchers in the UK and Canada, which appeared last week in Nature Cell Biology, says that the best way to treat Alzheimer’s is to trick the brain into not producing the tau protein, which forms the aggregates called tangles. The scientists, who studied the chemistry and structure of the tau protein, designed an enzyme inhibitor which uses a sugar molecule to lower the production of the protein. With the new insights, scientists hope that the management of Alzheimer’s disease, which is estimated to cost more than $300 billion a year-may become easier. Perhaps here may soon be drugs that can treat the worst of neuro degenerative disorders.

Constipation: the Solution

Treatment can be started once the cause of constipation can be found. Slow transit constipation requires aggressive medical or surgical management. But only approximately 60% of patients with constipation are found to have such a physiologic disorder and half of them with colonic transit delay and half with evacuation disorder.

Patients with slow transit constipation are treated with bulk, osmotic, prokinetic, secretory, and stimulant laxatives. Some of the laxatives are fiber, psyllium, milk of magnesia, lactulose, polyethylene glycol (colonic lavage solution), lubiprostone, and bisacodyl. Latest treatment of constipation is aimed at increasing motility of intestines. For 3 to 6 months patient should be tried with medical management, but if it fails to give proper result than surgical management can be decided. But surgical management should not be considered if motility disorder is present, because it will not improve the problem of constipation.

Largest number of patient with constipation are of idiopathic type that is a cause can not be ascertained and vast majority of patients complaining of constipation, basically have some form of misunderstanding regarding constipation.

The following measures can relieve/improve the problem of constipation:

1. Person suffering from constipation should do regular exercise for about half hour everyday. Moderate exercise like brisk walking or cycling is very good examples of moderate exercise. Aerobics can also be done every day. Exercise should be done at least for five days a week, less than five days a week will not give desired result.
2. Consume sufficient quantity of fiber in the diet. This is the most important aspect of constipation management. For this one should have clear idea of food and nutrition and fiber diet. Some of the examples of fiber diets are whole grain, fruits, vegetables, roots and tubers. Refined food is low in fiber and consumption of these refined foods is the main reason of constipation in western countries. Any natural food without refining is good source of fiber. Consumption is not as common in developing countries as in western countries is due to consumption of large quantity of natural food without refining like whole grain (staple food), vegetables and fruits. Meat, fish and other animal products contain less amount of fiber.
3. Drink plenty of water to get relief from constipation, drink about 3 to 4 liters of water every day. This help to soften the stool and the stool volume also increases which make it easier to pass.
4. Regularize the bowel habit, preferably in the morning. Make it a habit, it may take some time to become habit but it is a very good habit to solve problem of constipation. It is said that habit is second nature, and once you can make a second nature you can solve your problem of constipation.
5. Do not make habit of using laxatives for minor constipation. If all the above mentioned strategies fail than only one should go for laxatives. At first try natural laxatives like husk of isopgola. If this fail than go for other types.
6. Change your lifestyle. This is one of the important strategies to get rid off constipation. You should know what you are eating and try to eat healthy.

The above strategies can be of very much use if one is suffering from constipation.

Constipation: The Problem

Constipation is a common problem in clinical practice. Because of the wide range of normal bowel habits, constipation is difficult to define precisely. Constipation refers to persistent, difficult, infrequent, or seemingly incomplete defecation. It is a common problem in clinical practice.

Most persons have at least three bowel movements per week in western countries due to less fiber in the diet. In developing countries the frequency of stool is much more than western countries due to high fiber in their diet. But low stool frequency alone is not the sole criterion for the diagnosis of constipation.

Many constipated patients have a normal frequency of defecation but they complain of hard stools, excessive straining, lower abdominal fullness and a sense of incomplete evacuation of bowel. Every individual patient’s symptoms must be investigated in detail and ascertain what is meant by “constipation” or “difficulty” with defecation.

The consistency and form of stool depends on frequency of bowel habit, the longer the stool stay inside the harder it becomes. Hard, pellety stools occur with longer bowel transit and soft, loose and watery stool occur in shorter transit time. If stool is hard and large in quantity it is difficult to expel. Cultural and psychological factors are also being important. In some cultures great importance is given to daily defecation and will become greatly concerned when he or she misses a daily bowel movement.

Causes of constipation:

Chronic constipation usually results from insufficient fiber or fluid intake or from disordered colonic transit or anorectal function. Certain drugs, advancing age, or in association with a large number of systemic diseases that affect the gastrointestinal tract may cause constipation. Constipation of recent onset may be tumor or stricture. The following are the causes of constipation in adults:

Constipation of recent onset:

• Colonic obstruction due to stricture, tumor, or ischemia (death of tissue due to lack of blood supply) can cause constipation.

• Anal sphincter spasm as seen in piles or anal fissure can cause constipation.

• Many types of drugs (medicines) can cause constipation.

Chronic constipation:

• Disorders of rectal evacuation like rectal prolapse, or rectocele can cause chronic constipation.

• Irritable bowel syndrome can cause chronic constipation.

• Psychiatric disorders like eating disorder, drugs and depression can cause chronic constipation.

• Many types of drugs like anti depressants can cause chronic constipation.

• Generalized muscle disease like systemic sclerosis can cause chronic constipation.

• Finally idiopathic (unknown) cause of constipation, which is by far the commonest type of constipation.

The last type mentioned above that is the idiopathic constipation is the most commonly encountered in clinical practice. The cause is not known, and it has to be managed symptomatically. Psychogenic form of constipation is also very common. This type is to some extent self induced, without knowing that the person is going to have problems. Some people can not evacuate the bowel unless they get to smoke (cigarette) and some people without sitting in toilet with a news paper. These are only few of the examples of psychogenic constipation, there are many more examples.