Note: THIS IS NOT COMPLETE BOOK ? ( these are samples of some pages )
GENETICS AND ENVIRONMENT
Deoxyribonucleic Acid (DNA) is also called “thread of life”, as it is capable of self duplication , resulting in growth and development in all living cells. The diagram below, Figure 1-3, illustrates the phenomenon of duplication of DNA . :
Figure 1-3: Duplication of DNA
As described earlier, the body is made up of cells which contain chromosomes. The chromosomes (rod shaped structures) are found in the nucleus of the cell that hold the genetic material called genes , which carry hereditary instructions that act as the blueprints for life. Each chromosome contains deoxyribonucleic acid or DNA. When the cell divides, the two new cells have identical DNA molecules. Each chromosome contains hundreds of genes. Recent human genome studies have determined that there are about 100,000 genes in humans. The unique combinations of genes give each of us our individual characteristics. Passed from parent to child, genes constitute the genetic makeup of each individual. At conception, 23 (22+1)chromosomes from each parent join to make 23 pairs (2n=46). Genes determine traits, such as tissue and organ development, determination of sex, blood type, hair color, eye color, skin color, etc. Some genes are dominant and some are recessive. For example, the gene for brown eyes is dominant over the recessive gene of blue eyes, dark hair dominant over light hair, farsightedness over normal vision, etc. The genes encode genetic information for the synthesis of specific enzyme molecules , and the enzymes in turn promote the metabolic interactions. Gene expression is also influenced by environmental factors that may enhance the development of a trait. At the end of each chromosome, there are telomeres. Scientists have found that the decrease in the length of telomeres and levels of the telomerase are markers of aging, disease risk, and premature death in several types of cancer. Dr. Elizabeth Blackburn won a Nobel Prize for researching the relationship between telomere length and influence of telomerase enzyme. Scientists liken telomeres to the plastic caps found on shoe laces as they protect the chromosomes from wearing away or sticking together. Telomeres protect our genetic data as cells divide. Scientists now use telomere length and levels of telomerase as indicators of cellular aging. Cells can divide only about 50 to 70 times in humans with the telomeres getting progressively shorter until the cells become aged and die. This phenomenon is related to aging and the physiological/ stress. There are several stresses which can accelerate cellular aging: Oxidative stress ; : Oxidative stress results from free radicals , which are unstable molecules , capable of stripping electrons from other molecules , in the effort to become stable. When you produce more free radicals by smoking, excessive alcohol intake,smog or inflammation, you create oxidative stress. Oxygen is very essential for life. The same oxidation process that causes a cut apple to turn brown , or metal to rust , due to free radicals of oxygen also causes your body to ‘rust’ inside. Metabolic stress : Metabolic stress results from overeating, especially when eating energy dense foods that are high in animal fats and sugar with high glycemic index. or by the poor nutrition due to lack of proteins and minerals. Psychological or physical stress : Psychological or physical stress raises your blood pressure, heart rate, and stress-related hormones like adrenaline and cortisol. Sustained high stress depletes the body’s reserves. It hampers immunity and contributes to decreased telomere length. A blood test has been designed in Britain to measure length of telomeres and correlate it with the speed of aging in humans. According to some research, this test will be able to determine whether a person’s ‘biological age’, as measured by the length of their telomeres, is older or younger than their actual chronological age. There is an indication that shorter telomere may cause shorter lifespan. It is not yet known whether longer telomeres are going to give you longer lifespan. Some viruses, such as COVID-19 do not have their own DNA and are dependent on the host DNA to replicate and multiply.
DEFENSE MECHANISMS AGAINST VIRAL INFECTIONS
When the human immune system encounters a virus, it produces antibodies , which binds to the virus and neutralizes its infectivity or marks it for destruction. This phenomenon is most effective to defend host cells. Antibody presence in blood serum is often used to determine whether a person is exposed in the past , with tests, such as ELISA . (Enzyme-Linked Immunosorbent Assay). This test detects and measures antibodies in the blood related to certain conditions, such as viral or bacterial infection. The Immune system protects the body against antigens (bacteria, viruses, fungi, and other pathogens). It produces white blood cells or leukocytes, including B cells and T cells. If the immune system is weakened, it becomes vulnerable to all kinds of diseases. Immunoglobulin or antibodies react to the specific antigen. Immunity is of two types: active or passive. Active immunity describes the body’s own determination and response to disease or by vaccination. Passive immunity describes the introduction of antibodies from elsewhere, either by injection of antibodies or from the mother. Unlike active immunity, which creates “memory”, cells are the immediate recognition of repeated invasion by a pathogen. Passive immunity is usually only temporary. When someone has fever, it may be a sign that the body’s immune system is working to fight off an infection and may develop antibodies to fight off future invasion of the same pathogen. The immune system is compromised or weakened under stress. It is crucial to alleviate stress so that the Immune system can function at the optimum level. Some techniques are described in ‘Stress Management’ . Nutrition plays a major role in optimizing the effectiveness of the immune system. Fetal undernourishment can cause a lifelong impairment of the immune system. Similarly, Nutritional deficiency in elderly can lower the efficiency of the immune system and they are vulnerable to infectious diseases, especially viral diseases like coronavirus. Mortality rate of people over 60 is higher than other populations. As people age, the decline in immune function is related to decreasing vitamin D levels. T-cells have a symbiotic relationship with vitamin D. The immune system plays a crucial role in repair and regeneration of cells. Inflammation is one of the first responses of the immune system to infection. The symptoms of inflammation are redness, swelling, heat, and pain due to increased blood flow. Inflammation is produced by cytokines , which are released by injured or infected cells. Cytokines are essential but over production can cause a ‘cytokine storm’. Optimum level of cytokines is essential for better efficiency of the immune system. Ultimate prevention and eradication of COVID-19 will depend upon herd immunity and vaccination. The second defense mechanism is Cell-mediated immunity , which involves immune cells known as T cells . They recognize strange viral fragments on the surface of cells and activate the immune system.
● I nterferon is a substance that is naturally produced when an infection is detected and stimulates other parts of the immune system. It is a kind of antiviral remedy.
● Vaccination against virulent is a preventive measure. Although it is a long process, once proved safe, it can save a lot of lives. A typical example is influenza H1N1 vaccine.
● Research is being carried on preventative and symptom suppression at global level. Recently FDA has approved use of hydroxychloroquine even though it needs further studies.
COVID-19 seems to spread easily from person to person especially in congested homes, hospitals, nursing homes, and other crowded places. This virus is considered a zoonotic spillover, meaning that it can jump from animals, such as bats and snakes. A recent incidence at the New York Zoo included a Malayan tiger, Nadia, tested positive with Covid-19. This Tiger interacted with a zoo staffer who was a carrier of COVID-19. This will be a dangerous process once it is a widespread phenomenon. COVID-19 can be carried on ony droplets released by coughing and sneezing. It may also be transmited when someone touches a contaminated surface and then touches his/her mouth, eyes or nose. As soon as the viral particles get into the human airway, it penetrates cell membrane and nuclear membrane and hijacks the DNA of the host cell. At that moment it is able to replicate itself quickly. In the beginning, the virus enters the nasal passage or throat and starts replicating which is a highly contagious stage. Eventually the particles enter lungs and start infecting the neighboring cells. Sometimes the host may not show symptoms for a few days. The host becomes a carrier and is able to transmit virus particles to the next host. This asymptomatic carrier is more dangerous because you are unaware of the carrier. COVID-19 is known to survive several hours on countertops, door knobs, faucets, contaminated clothes, jewelry, cardboard, etc. There are a number of modes of transmission such as: Person to person, especially from people who are in close contact, i.e. within 6’
● Through respiratory droplets produced when an infected person coughs or sneezes
● Talking face to face in close vicinity spreading fine particles
● Some particles will settle on objects in close vicinity
● By touching surface of contaminated places then hand, mouth, nose and eyes , spreads the virus
● New evidence suggests transmission from animals to human and vice versa.
Dr. Yoshimori Ohsumi won the Nobel Prize in 2016 for his work on autophagy. A cell is capable of synthesizing degraded cell parts to maintain cellular integrity. Cells respond to different types of stresses , such as starvation and physical exertion. Autophagy can also help the body get rid of invaders such as bacteria, viruses , and fungi, and utilize those for rebuilding new cells. It can also help counteract the negative effects of aging, type II diabetes, and Parkinson’s diseases. One can simply use the analogy of a new car to understand autophagy. After a few years of use, it may suffer wear and tear and eventually no longer be performing as usual. One can replace worn out parts to maintain its integrity. Similarly worn down body cells are repaired by using recycled old parts and rebuilding new cells. This process is constantly happening in living cells. This phenomenon can be expedited by carbohydrate restriction, protein, and lipid moderation. Ketosis and autophagy have some common features and can be used effectively to treat a number of human ailments. There is a lot of interest in the scientific community to use these principles for optimum health performance.
THE DIGESTIVE SYSTEM
The digestive system is also called gastrointestinal tract (GI) or alimentary canal converts food into sugars, amino acids, fatty acids etc so that it is capable to get converted into energy and primarily acts as a source of nourishment. The GI tract is a continuous tube like structure that begins at the mouth, and through the esophagus, stomach, small intestine, large intestine, and ends at the rectum and anus. Other organs of the GI tract are liver, pancreas, etc. The mechanical and chemical breakdown of food begins in the mouth. The teeth grind food into small pieces when that is mixed with saliva, enzymatic action starts converting starch into sugar. The stomach contains glands that secrete gastric juices containing enzymes, chiefly pepsin, and hydrochloric acid (Hcl) which further breaks down the food into smaller particles. The carbohydrates ultimately are converted into glucose which passes through the stomach quickly. Ordinarily food leaves the stomach in 3 to 5 hours. Proteins and fats take longer to break down and get absorbed. The end of the stomach opens into the duodenum which is the first section of the small intestine where food is mixed with secretions from the liver, gallbladder , and pancreas which begin to break down proteins into amino acids, carbohydrates into glucose, and lipids into fatty acids and glycerin. The liver is the largest organ of the human body, weighing about four pounds. It acts as storage for fat-soluble vitamins , such as vitamins A, D, glycogen , and blood coagulation factors. It manufactures enzymes, cholesterol , and vitamins. The liver produces bile which helps in the digestion of fats. It also filters out harmful substances and waste.The pancreas secretes ahormone called insulin which metabolizes sugars.Pancreatic juices contain different digestive enzymes such as lipase which splits fat , and protease which splits proteins. All the nutrients are absorbed through villi in the intestinal linings into the bloodstream. The substances which are not digestible and remaining water enter into the large intestine, rectum , and are evacuated through the anus.
HOW DOES EXERCISE HELP TO BOOST IMMUNITY
● Exercise increases metabolic rate, thereby burning more calories for an extended period after the activity. This residual effect (after burn) is the greatest benefit from burning calories by exercising.
● Fat is burned basically in the muscles, therefore it becomes crucial to build muscle mass to shed extra fat. One of the effective methods to build muscle mass is by Anaerobic exercises, accompanied by balanced nutrition with an adequate amount of proteins. All the methods described here are without the use of drugs (non-pharmacological). All the concepts are derived from scientific research, human experience from different cultures and common sense. Resistive muscle training will develop musculature. Start with a light exercise program with 4 to 5 pushups and squats using your own body mass as resistance. Increase by 15 minutes per week for a month. Eventually it will become a habit. See appendix 1, for illustrations of various exercises. Another concept is becoming popular, called high intensity interval training to burn fat. It alternates between very strenuous bursts of activity and less intensively recovery time. It involves 30 seconds of gentle running, 20 seconds at moderate pace, and then 10 seconds of full-out effort for a total of 1 minute. Do three replications of five minutes each with two minutes of rest.in between each.S 13.
STRESS MANAGEMENT AND IMMUNE SYSTEM
There is evidence that stress can suppress the immune system, increasing susceptibility to viral, fungal and bacterial infections. Moreover, the build- up of stress can contribute to anxiety and depression which may further affect efficiency of the immune system. There are ways to elicit the relaxation response to neutralize stress such as ;